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| Microstructure evolution in silty soil during drying |
| SUN Wenjing1，WEI Guang1，CUI Yujun2，SUN Dean1 |
(1. Department of Civil Engineering，Shanghai University，Shanghai 200444，China；2. Laboratoire Navier，École des Ponts ParisTech，Paris 77455，France)
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Abstract The drying-induced micro-structure evolution of reconstituted Jossigny silt that contains 34% clay-sized fraction was investigated through mercury intrusion porosimetry tests on samples with different water contents. During the preparation of soil samples，the macro-cracks were avoided as far as possible. The final cumulative intrusion void ratio decreased upon drying and became almost unchanged when the water content was lower than the shrinkage limit. The inaccessible pores increased and reached a stable state during drying. The pore size distribution(PSD) curve was shifted left to smaller diameter. However，further drying led PSD curve to shift right to larger diameter，which represented the special microstructure evolution in silty soil during drying because of the microstructure composition of silty soil. Moreover，a bump in PSD curves at the diameter range from 0.1 to 1 ?m indicated the possible occurrence and development of the internal micro-fissures. Once the silt slurry was dried to unsaturated state，the microscopic fissures might begin to develop in the clay fraction that coated the silt grains and in the interface between the silt grain and clay particles. These internal micro-fissures identified in the residual shrinkage stage are different from the macro-cracks due to desiccation.
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2017, Vol. 36 
